Indole derivatives substituted with long-chain alcohols and medicaments containing them

ABSTRACT

Provided is an indole long-chain alcohol, or a hydrate or an isomer thereof, represented by the following formula (I): 
     
       
         
         
             
             
         
       
         
         
           
             wherein R 1 , R 2 , R 3  and R 4  each independently represent a hydrogen atom, a methyl group, an acetyl group, or a hydroxyl group, and n represents a number from 0 to 20; and a medicinal composition comprising the same. The indole long-chain alcohol (I) exhibits an excellent nerve growth promoting effect, as well as potent antioxidative and anti-tumor effects, and is therefore useful as a prophylactic and/or therapeutic agent for cerebral diseases including dementia diseases, and malignant tumors including brain tumors.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 10/504,484, filed on Aug. 12, 2004, which is a 35 U.S.C. §371National Stage patent application of International patent applicationPCT/JP02/01192, filed on Feb. 13, 2002.

TECHNICAL FIELD

The present invention relates to an indole long-chain alcohol whichexhibits an excellent nerve growth promoting effect and potentantioxidative and antitumor effects, and is therefore useful as apreventive and/or therapeutic agent for cerebral diseases typified bydementia or malignant tumors such as brain tumor; and a medicamentcontaining the compound.

BACKGROUND ART

It is considered that the main lesion of Alzheimer's disease isdegeneration and defluvium of cholinergic neurons. At present, acholinesterase inhibitor or a muscalinic receptor agonist is used forthe treatment of said disease. Such a medicament alleviates dementiasymptomatically but cannot stop or retard the progress of the morbidity.There has also been made an attempt to treat Alzheimer's disease byadministering a nerve growth factor (NGF) into the brain. NGF isexpected to suppress degeneration and defluvium of neurons due to itsneuron growth action, thereby terminating or retarding the progress ofdementia. However, since NGF is a protein having a molecular weight of12,000, it cannot pass through the blood-brain barrier and itsadministration route is confined only to intraventricularadministration, which is not practical for the treatment of humanbeings. If there is such compound that exhibits an NGF-like action andhas a molecular weight low enough to pass through the blood-brainbarrier or such compound that can enhance the synthesis of NGF in thebrain, it will be promising as a remedy effective for treatingAlzheimer's dementia.

Based on such an idea, a substance which promotes and/or reinforcesproduction of NGF has been searched, and it has been proved thatlong-chain aliphatic alcohols such as n-hexacosanol stimulate nervegrowth factor in vitro and can pass through the blood-brain barrier invivo (Japanese Patent Application Laid-Open No. 502167/1992).

DISCLOSURE OF THE INVENTION

Accordingly, an object of the present invention is to provide amedicament comprising a compound which is orally administrable, readilytransferred into the brain, and permits extension of neurite in thebrain or activates the synthesis and secretion of NGF.

The present inventors have synthesized a long-chain alcohol derivativehaving an indole skeleton and investigated its pharmacological action.As a result, it has been found that an indole long-chain alcoholrepresented by the formula (I) shown below exhibits an excellent nervegrowth promoting effect and potential antioxidative and anti-tumoreffects, and is therefore useful as a preventive and/or therapeutic drugfor cerebral diseases such as dementia or malignant tumors such ascerebral tumor, to complete the present invention.

In one aspect of the present invention, there is thus provided an indolelong-chain alcohol represented by the following formula (I):

wherein R¹, R², R³ and R⁴ each independently represents a hydrogen atom,a methyl group, an acetyl group or a hydroxyl group and n stands for anumber from 0 to 20.

In another aspect of the present invention, there is also provided amedicine comprising the compound of the formula (I) as an effectiveingredient.

In a further aspect of the present invention, there is also provided anerve growth promoting agent comprising the compound of the formula (I)as an effective ingredient.

In a still further aspect of the present invention, there is alsoprovided a preventive and/or therapeutic drug for dementia and/ormalignant tumors, which comprises the compound of the formula (I) as aneffective ingredient.

In a still further aspect of the present invention, there is alsoprovided a medical composition comprising the compound of the formula(I) together with a pharmaceutically acceptable carrier.

In a still further aspect of the present invention, there is alsoprovided use of the compound of the formula (I) for the manufacture of amedicament.

In a still further aspect of the present invention, there is alsoprovided use of the compound of the formula (I) for the manufacture of anerve growth promoting agent.

In a still further aspect of the present invention, there is alsoprovided use of the compound of the formula (I) for the manufacture of apreventive and/or therapeutic drug for dementia and/or malignant tumor.

In a still further aspect of the present invention, there is alsoprovided a method for treating cerebral diseases and/or malignant tumorswhich comprises administering an effective amount of the compound of theformula (I) to a patient in need thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates the effect of the compounds of the invention onneurite outgrowth; and

FIG. 2 illustrates the effect of the compounds of the invention onpreventing hemolysis of human blood cells induced by free radicals.

BEST MODE FOR CARRYING OUT THE INVENTION

In the formula (I), R¹, R², R³ and R⁴ can be any of the above-describedgroups and are particularly preferably hydrogen atom. n stands for anumber from 0 to 20, preferably 2 to 18, more preferably 6 to 16, andparticularly preferably 8 to 14.

The compound (I) may be in the form of a hydrate. There are many isomersin the compound (I) and these isomers are also embraced in the presentinvention.

The invention compound (I) can be prepared, for example, in accordancewith the following reaction scheme:

wherein Ar represents an aromatic hydrocarbon group, X¹ and X² eachrepresents a halogen atom, R⁵ represents a hydroxyl-protecting group andR¹, R², R³, R⁴ and n have the same meanings as described above.

Specifically, an indole-3-carboxyaldehyde (A) is reacted with anarylsulfonyl halide to give Compound (B), which is in turn reacted withCompound (C) according to Wittig reaction to give Compound (D), and thenCompound (D) is halogenated to remove the hydroxyl-protecting grouptherefrom to give Compound (E), and then the amino-protecting group inthe Compound (E) is removed to obtain the compound (I) of the invention.

As the arylsulfonyl halide, p-methoxybenzenesulfonyl chloride can beillustrated. The reaction between the indole-3-carboxyaldehyde (A) andthe arylsulfonyl halide is preferably conducted in the presence of analkali such as sodium hydroxide.

As the hydroxyl-protecting group (R⁵) in the Compound (C) used in theWittig reaction, preferred is a group removable by hydrogenation, suchas, for example, benzyl group. The Wittig reaction is preferablyconducted by reacting Compound (C) with n-butyl lithium, followed byreaction with potassium t-butoxide and then with Compound (B).

Hydrogenation of Compound (D) is preferably conducted by reacting itwith hydrogen in the presence of, for example, a palladium catalyst. Inthe subsequent reaction for eliminating the arylsulfonyl group, anamalgam hydroxide and sodium hydrogenphosphate are preferably used.

Since the resulting compound (I) exhibits an excellent nerve growthpromoting effect and potent antioxidative and antitumor effects, and hasa molecular weight low enough to pass through the blood-brain barrier,it is useful as a preventive and/or therapeutic drug for cerebraldiseases typified by dementia of animals including human being andmalignant tumors such as cerebral tumor.

The medicament according to the present invention can be administeredeither orally or parenterally (such as intramuscular, subcutaneous,intravenous or suppository). In preparing these dosage forms, it ispreferred to use a medical composition containing the compound (I) ofthe invention and a pharmaceutically acceptable carrier. Oralpreparations can be formulated into tablets, coated tablets, granules,capsules, solutions, syrups, elixirs, or oily or aqueous suspensions ina manner known per se in the art after adding to the compound (I) anexcipient and, if necessary, a binder, a disintegrator, a lubricant, acolorant and/or a corrigent. Examples of the excipient include lactose,corn starch, sucrose, glucose, sorbitol and crystalline cellulose.Examples of the binder include polyvinyl alcohol, polyvinyl ether, ethylcellulose, methyl cellulose, gum arabic, tragacanth, gelatin, shellac,hydroxypropyl cellulose, hydroxypropyl starch and polyvinyl pyrrolidone.Examples of the disintegrator include starch, agar, gelatin powder,crystalline cellulose, calcium carbonate, sodium bicarbonate, calciumcitrate, dextran and pectin; and examples of the lubricant includemagnesium stearate, talc, polyethylene glycol, silica and hardenedvegetable oil. As the colorant, pharmaceutically acceptable ones can beused. Examples of the corrigent include cocoa powder, menthol, aromaticacid, peppermint oil, camphor and cinnamon powder. The tablets andgranules may be applied with sugar coating, gelatin coating or the likeas needed.

The dose of the medicine of the invention varies depending on thedisease to be treated, administration route, symptoms and weight of apatient. For a human adult, the daily dose of the compound (I) will beusually within a range of from 0.001 to 1000 mg/day, and preferably from0.1 to 100 mg/day. This daily dose is administered once a day or in 2 to4 portions a day.

EXAMPLES

The present invention will be hereinafter described in further detail byway of examples. It should however be borne in mind that the presentinvention is not limited to or by these examples.

Reference Example 1

3-indolecarboxyaldehyde (1.003 g, 6.91 mmol) was dissolved in 20 mL ofdry dichloromethane, and then sodium hydroxide (410 mg, 10.24 mmol) wasadded thereto. After allowing to stand for 15 minutes at roomtemperature, the resulting mixture was added with4-methoxybenzenesulfonyl chloride (2.112 g, 10.22 mmol) and was allowedto stand again at room temperature for 12 hours. To the reactionmixture, 100 mL of ammonium chloride was added and the mixture wasextracted with 100 mL of ethyl acetate three times. The combined organiclayer was washed with saline, dried over anhydrous magnesium sulfate andthen concentrated. The residue was recrystallized to give1-(4-methoxybenzensulfonyl)-3-indolecarboxyaldehyde as pearl-like pinkcrystals.

Melting point: 138 to 139° C.

¹H-NMR (200 MHz): 3.81(s,3H,H-9), 6.94(d,J=9.1 Hz,2H,H-3″,5″),7.32-7.45(m,2H,H-5,6), 7.91(d,J=9.1 Hz,2H,H-2″,6″), 7.87-7.96(m,1H,H-4),8.23(s,1H,H-2), 8.25(dd,J=6.9 Hz,J=2.7 Hz,1H,H-7), 10.09(s br,1H,H-8).

¹³C-NMR (50 MHz): 55.81(C-9), 113.25(C-7), 114.94(C-3″,5″), 122.26(C-3),122.60(C-4,6), 125.01(C-5), 126.27(C-2″,6″), 128.63(C-3′), 129.61(C-7′),135.23(C-1″), 136.24(C-2), 164.54(C-4″), 185.34(C-8).

Reference Example 2

A solution of 15-benzyloxypentadecyltriphenyl phosphonium bromide (755mg, 1.14 mmol) dissolved in 10 ml of tetrahydrofuran (THF) was addeddropwise to n-butyl lithium (1.5M in hexane, 0.8 mL, 1.20 mmol) at −78°C. in an argon gas atmosphere. After reaction at room temperature for 15minutes, potassium t-butoxide (131 mg, 1.16 mmol) was added to thereaction mixture at 0° C. The resulting solution was then allowed tostand at room temperature for 15 minutes. After the solution was cooledagain to −78° C., a THF solution of1-(4-methoxybenzenesulfonyl)-3-indolecarboxyaldehyde (307 mg, 0.97 mmol)was slowly added to the solution. The resulting mixture was allowed tostand at −78° C. for 1 hour, and then allowed to stand at 0° C. for 1.5hours. Ammonium chloride (50 mL) was added to the mixture and theresulting mixture was extracted three times with 60 ml of ethyl ether.The combined organic layer was washed with saline, dried over anhydrousmagnesium sulfate and then concentrated. The residue was purified bychromatography on a silica gel column to give3-(16-benzyloxyhexadecenyl)-1-(4-methoxybenzenesulfonyl)indole as awhite solid.

¹H-NMR (200 MHz), δ: 1.26(s br,20H,H-12 to H-21),1.46-1.65(m,4H,H-11,22), 2.32(m,2H,H-10), 3.47(t,J=6.6 Hz,2H,H-23),3.77(s,3H,H-25), 4.51(s,2H,H-24), 5.82(dt,J=11.1 Hz,J=6.9 Hz,1H,H-9),6.40(d,J=11.1 Hz,1H,H-8), 6.86(d,J=8.7 Hz,2H,H-3″,5″),7.21-7.36(m,7H,H-2′″ to H-6′″, H-5,6), 7.51(s,1H,H-2), 7.53(d,J=6.9Hz,1H,H-4), 7.82(d,J=8.7 Hz,2H,H-2″,6″), 7.99(d,J=7.6 Hz,1H,H-7).

¹³C-NMR (500 MHz) δ: 26.35(C-10), 29.83(C-11 to C-22), 55.75(C-25),70.70(C-23), 72.99(C-24), 113.74(C-7), 114.56(C-9), 117.58(C-3″,s5″),119.41(C-3), 119.71(C-5), 123.31(C-4), 123.58(C-6), 124.92(C-2″,6″),127.61(C4′″), 127.74(C-3′″,5′″), 128.49(C-2′″,6′″), 129.18(C-8),129.90(C-3′), 131.25(C-7′), 134.79(C-1″), 135.02(C-2), 138.92(C-1′″),163.92(C-4″).

In a similar manner to Reference Examples 1 and 2,3-(10-benzyloxydecenyl)-1-(4-methoxybenzenesulfonyl)indole (yield: 70%),3-(12-benzyloxydodecenyl)-1-(4-methoxybenzenesulfonyl)indole (yield:87%) and 3-(14-benzyloxytetradecenyl)-1-(4-methoxybenzenesulfonyl)indole(yield: 88%) were obtained.

Reference Example 3

3-(16-benzyloxyhexadecenyl)-1-(4-methoxybenzensulfonyl)indole (530 mg,0.86 mmol) was dissolved in 25 mL of ethanol and added to palladiumsupported on activated charcoal (5%, 50 mg). The resulting mixture wasallowed to stand at room temperature for 3 hours under 1 atmosphericpressure of hydrogen. After filtration, the reaction mixture wasextracted with ethyl ether. The organic layer was concentrated underreduced pressure. The residue was purified by flash chromatography togive 3-(16-hydroxyhexadecyl)-1-(4-methoxybenzenesulfonyl)indole as awhite solid (417 mg, 92%).

¹H-NMR (200 MHz) δ: 1.26(s br,24H,H-10 to H-21), 1.62(m,4H,H-9,22),2.63(t,J=7.4 Hz,2H,H-8), 3.64(t,J=6.4 Hz,2H,H-23), 3.77(s,3H,H-24),6.85(d,J=8.8 Hz,2H,H-3″,5″), 7.25(m,2H,H-5,6), 7.29(s,1H,H-2),7.47(d,J=6.6 Hz,‘H,H-4), 7.79(d,J=8.8 Hz,1H,H-2″,6″), 7.97(d,J=7.6Hz,1H,H-7).

¹³C-NMR (50 MHz) δ: 24.93(C-21), 25.80(C-9), 28.94(C-20), 29.70(C-10 toC-19), 32.87(C-8), 55.63(C-24), 63.14(C-23), 113.81(C-7), 114.36(C-9),119.54(C-3″,5″), 122.64(C-4), 122.89(C-6), 123.66(C-3), 124.50(C-5),128.99(C-2″,6″), 129.99(C-3′), 131.31(C-7′), 134.85(C-1″), 135.44(C-2),163.60(C″-4).

In a similar manner to Reference Example 3,3-(10-hydroxydecyl)-1-(4-methoxybenzenesulfonyl)indole (yield: 92%),3-(12-hydroxydodecyl)-1-(4-methoxybenzenesulfonyl)indole (yield: 92%)and 3-(14-hydroxytetradecyl)-1-(4-methoxybenzenesulfonyl)indole (yield:93%) were obtained.

Example 1

To a solution of3-(16-hydroxyhexadecyl)-1-(4-methoxybenzenesulfonyl)indole (400 mg, 0.72mmol) dissolved in 20 ml of dry methanol were added disodiumhydrogenphosphate (205 mg, 1.44 mmol) and amalgam chloride (6%, 4 g) at0° C. under argon gas. After the resulting mixture was allowed to standat room temperature for 12 hours, 50 mL of ammonium chloride was addedthereto. The resulting mixture was extracted three times with 60 ml ofethyl ether. The combined organic layer was washed with saline, driedover anhydrous magnesium sulfate and then concentrated. The residue waspurified by chromatography on a silica gel column to give3-(16-hydroxyhexadecyl)indole (Compound 1) as a white solid (204 mg,75%).

Melting point: 79 to 80° C.

¹H-NMR (200 MHz) δ: 1.27(s br,24H,H-10 to H-21), 1.57(m,2H,H-22),1.72(m,2H,H-9), 2.76(t,J=7.6 Hz,2H,H-8), 3.64(t,J=6.4Hz,2H,H-23),6.97(s,1H,H-2), 7.15(m,2H,H-5,6), 7.35(d,J=7.6 Hz,1H,H-4), 7.62(d,J=7.6Hz,1H,H-7), 7.93(s br,1H,H-1)

¹³C-NMR (50 MHz) δ: 25.30(C-21), 25.89(C-9), 29.83(C-10 to C-20),30.32(C-8), 32.97(C-22), 63.26(C-23, 111.15(C-7), 117.38(C-3),119.15(C-4,6), 121.12(C-5), 121.94(C-2), 127.79(C-3′), 136.52(C-7′)

IR (KBr): 3416(s br,O—H,N—H), 3049(w,═C—H), 2916, 2849(s,C—H), 1638,1618(m,C═C), 1474, 1457(m,C—H), 1061(w,C—O), 741(m,C—H)

UV (acetonitrile): λmax: 203 nm (ε18864), 222 nm (ε27571), 281 nm(ε5880)

MS (EI): 357.3 (M⁺,37), 144.2(C₁₀H₁₀N,4), 130.3(C₉H₈N,100)

In a similar manner to Example 1, the following compounds were obtained.

-   3-(2-hydroxyethyl)indole (liquid) (Compound 2)-   3-(10-hydroxydecyl)indole (melting point: 55 to 56° C.) (Compound 3)-   3-(11-hydroxyundecyl)indole (melting point: 60 to 61° C.) (Compound    4)-   3-(12-hydroxydodecyl)indole (melting point: 66 to 67° C.) (Compound    5)-   3-(14-hydroxytetradecyl)indole (melting point: 72 to 73° C.)    (Compound 6)

Test Example 1 Effect on Neurite Outgrowth and Neuron Survival

This experiment was conducted in accordance with the method of Luu, etal. (C. Girlanda-Junges, F. Keyling-Bilger, G. Schemitt & B. Luu,“Effect of Cyclohexenonic Long Chain Fatty Alcohols on NeuriteOutgrowth. Study on Structure-Activity Relationship”, Tetrahedron, 54,7735-7748(1998)). Fetal rat neurons in primary cultures were treatedwith Compound 1 at the concentrations of 10⁻⁶ and 10⁻⁷ M, followed byincubation for 3 days. As illustrated in FIG. 1, the proportion of theneurons with neurites of 50 μm or longer was found to be higher in thetreated group than in the control group, which clearly shows thatCompound 1 has a potent neurite extension effect.

Test Example 2 Preventive Effect on Hemolysis in Human Blood CellsInduced by Free Radicals

An experiment was conducted in accordance with the method of D. Blache.FASEB J. et al. (E. Bourdon, N. Loreau & D. Blache. FABES J. “Glucoseand free radicals impair the antioxidant properties of serum albumin”,13, 233-244(1999)). The time required for 50% hemolysis (HT₅₀) wasmeasured and the extension of the time required for HT₅₀ compared withthat of a control group was plotted on a graph. In this experiment,Vitamin E was employed as a positive control. As illustrated in FIG. 2,the compounds of the invention (Compounds 1, 2 and 4) extended HT₅₀,thus exhibiting preventive effect on hemolysis. Particularly, Compound 4exhibited a strong effect.

Test Example 3 Induction of Differentiation and Apoptosis ofNeuroblastoma Cells

Human neuroblastoma cells, Lan-1 (Lan-1: a human neuroblastoma cell linewith M1 and M2 muscarinic receptors conjugated with intracellular Ca²⁺)were used to investigate the effects of the present compounds on theinduction of proliferation, differentiation and apoptosis. As shown inTable 1, the present compounds (Compounds 1, 3 and 4) exhibited strongereffects on induction of differentiation or apoptosis of neuroblastomacells rather than on proliferation of the cells.

TABLE 1 Day 5 Day 7 Concen- Day 1 Day 2 Pro- Pro- tration Prolifera-Differen- Apop- Prolifera- Differen- Apop- lifera- Differen- Apop-lifera- Differen- Apop- μM tion tiation tosis tion tiation tosis tiontiation tosis tion tiation tosis Control + − − ++ − − ++ − +/− ++ − +/−Comp'd 3 0.1 + + − + + − + − +/− ++ +/− +/− 10 +/− +++ − +/− ++ + +/−++ + +/− +++ + 100 − + ++ +/− + ++ +/− +++ ++ ++++ Comp'd 4 0.1 ++ −− + + − +/− +/− − ++ +/− − 10 + ++ − +/− ++ + +/− ++ − +/− ++ +/− 100+/− + +++ − − +++ + ++++ + ++++ Comp'd 1 0.1 + +/− − ++ +/− − +/− +/− −+/− + +/− 10 + ++ +/− + +++ +/− +/− +++ ++ +/− ++++ ++ 100 +/− +++ + −++++ + − + +++ − ++ +++ ++++: Extremely strongly stimulated(reinforced). +++: Very strongly stimulated (reinforced). ++: Stronglystimulated (reinforced). +: Stimulated (reinforced). +/−: No change. −:Decreased (weakened).

INDUSTRIAL APPLICABILITY

The present compound (I) has an excellent nerve growth promoting effect,an antioxidative effect and an antitumor effect and is therefore usefulas a preventive and/or therapeutic drug for cerebral diseases such asdementia or malignant tumors such as cerebral tumor.

1. A method for treating a cerebral dementia disease comprisingadministering to a patient in need thereof a therapeutically effectiveamount of an indole long-chain alcohol, or a hydrate or an isomerthereof, according to the following formula (I):

wherein R¹, R², R³, and R⁴ each independently represent a hydrogen atom,a methyl group, an acetyl group, or a hydroxyl group, and n represents anumber from 0 to
 9. 2. The method according to claim 1, wherein nrepresents a number from 0 to
 3. 3. The method according to claim 1,wherein n represents a number from 3 to
 5. 4. The method according toclaim 1, wherein n represents a number from 5 to
 7. 5. The methodaccording to claim 1, wherein n represents a number from 7 to
 9. 6. Themethod according to claim 1, wherein the therapeutically effectiveamount of the indole long-chain alcohol is from 0.001 to 1000 mg/day. 7.The method according to claim 1, wherein the therapeutically effectiveamount of the indole long-chain alcohol is administered either once perday or in two to four divided doses per day.
 8. The method according toclaim 1, wherein the therapeutically effective amount of the indolelong-chain alcohol is administered orally or parenterally.
 9. A methodfor treating a malignant brain tumor comprising administering to apatient in need thereof a therapeutically effective amount of an indolelong-chain alcohol, or a hydrate or an isomer thereof, according to thefollowing formula (I):

wherein R¹, R², R³, and R⁴ each independently represent a hydrogen atom,a methyl group, an acetyl group, or a hydroxyl group, and n represents anumber from 0 to
 9. 10. The method according to claim 9, wherein nrepresents a number from 0 to
 3. 11. The method according to claim 9,wherein n represents a number from 3 to
 5. 12. The method according toclaim 9, wherein n represents a number from 5 to
 7. 13. The methodaccording to claim 9, wherein n represents a number from 7 to
 9. 14. Themethod according to claim 9, wherein the therapeutically effectiveamount of the indole long-chain alcohol is from 0.001 to 1000 mg/day.15. The method according to claim 9, wherein the therapeuticallyeffective amount of the indole long-chain alcohol is administered eitheronce per day or in two to four divided doses per day.
 16. The methodaccording to claim 9, wherein the therapeutically effective amount ofthe indole long-chain alcohol is administered orally or parenterally.